DELPHINIDA 
261 
small, not meeting in the middle line, but approxi- 
mating posteriorly. Vertebre: C7, D 11, L6, 
C 26; total 50. Cervical region comparatively 
long, and all the vertebre distinct, or with ir- 
regular unions towards the middle of the series, 
the atlas and axis being usually free. Manus 
small, short, and broad; second and third digits 
nearly equal, fourth slightly shorter. No dorsal 
fin. 
This genus is now represented only by the 
well-known Narwhal (Jf. monoceros), in which the 
horn-like tusk of the male often grows to a 
length of 7 or 8 feet. In very young animals 
several small additional teeth, irregular in number 
and position, are present, but these usually dis- 
appear soon after birth. 
The head is rather short and rounded ; the 
fore limbs or paddles are small and broad com- 
pared with those of most Dolphins ; and (as in the 
Beluga) the median dorsal fin, found in nearly 
all other members of the group, is wanting or 
replaced by a low ridge. The general colour of 
the surface is dark gray above and white below, 
but variously marbled and spotted with different 
shades of gray. In the general contour of the 
body the Narwhal resembles the White Whale 
or Beluga. - 
The Narwhal is essentially an Arctic animal, 
frequenting the icy cireumpolar seas, and but 
rarely seen south of 65° N. lat. Three instances 
have, however, been recorded of its occurrence 
on the British coasts, one in the Firth of Forth 
in 1648, one near Boston in Lincolnshire in 1800, 
while a third, which entangled itself among 
the rocks in the Sound of Weesdale, Shetland, 
in September 1808, is described by Fleming 
in the Memoirs of the IWernerian Society, vol. i. 
Like most other Cetaceans, it is gregarious in 
its habits, being usually met with in “ schools ” 
or herds of fifteen or twenty individuals. Its 
food appears to be various species of cephalo- 
pods, small fishes, and crustaceans. The pur- 
pose served in the animal’s economy by the 
wonderfully developed asymmetrical tusk—or 
“horn,” as it is commonly but erroneously 
called —is not known. As it is present only 
Fra, 90.—Upper surface of the skull of male Narwhal (Monodon monoceros), with the whole of both teeth exposed 
by remoyal of the upper wall of their alveolar cavities. 
